How effective is the progestogen pill?
Although emergency contraception is effective, it is not as reliable as regular planned contraception. Therefore, it should only be used in emergencies. The progestogen pill becomes gradually less effective the more time elapses after having unprotected sex. However, there is a good chance of preventing pregnancy if it is taken up to 72 hours after unprotected sex. If this pill is taken within 24 hours after unprotected sex, about 95 in 100 pregnancies are prevented. If it is taken between 25-48 hours after unprotected sex then about 85 in 100 pregnancies are prevented. If it is taken between 49 and 72 hours after unprotected sex, then about 58 in 100 pregnancies are prevented. It is sometimes used between 72 and 120 hours after unprotected sex but the chance of it working is much less than if it is taken within 72 hours.
